Incandescent-lamp socket.



No. 811,161. PATENTED JAI LAIO 1906. N. MARSHALL. INGANDESGENT LAMP SOCKET.

APPLICATION FILED MAILBI, 1904.

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UNITED STATES PATENT OFFICE.

NORMAN MARSHALL, OF NEWTON, MASSACHUSETTS. INCAN'DESC-ENTF-LAMPVSOQKET.

Specification of Letters Patent.

Patented Jan. 30, 1906.

Application filed March 31, 1904. Serial No. 200,974.

To all whom it may concern.-

Be it known that I, NORMAN MARSHALL, of

I Newton, in the county of Middlesex and State specification.

The invention relates to shells or casings forincandescent-lamp sockets, and more especially to the means for detachably connecting the parts of the shell together.

Incandescentfilamp sockets as commonly constructed are provided with an outer metallic shell or casing which surrounds and supports the insulating and current-carrying parts. This casing consists of a'cylindrical part open at the ends, which is called the shell, and a cap which closes one end of the shell and forms the means for connecting the socket to a fixture and supporting the parts of the socket. The shell and cap are so connected together that they may be'readily separated or secured together in assembling, wiring, or inspecting the socket. These parts are commonly formed ot thin sheet metal, and devices heretofore commonly used for detachably connecting them together have required the use of separate or additional pieces of metal secured to or in the cap or shell to reinforce the thin metal for the reception of the screws or other securing devices or to form a part of such devices.

In practicing my invention i form integral lugs in the cap or shell by drawing the thin metal radially inward or outward at the points where the lugs are to be formed and also form cooperating slots or recesses in the other part of the casing, which register with the lugs when the cap and shell are brought together. I have found that an integral lug may be formed in the thin metal of suflicientstrength and rigidity to form one member of an eflicient connecting device by drawing the metal radially in ward or outward. I have also found that the metal may be thus drawn without inury to the shell (or cap) and without destroying the temper and resiliency of the shell (or cap) by a local application of heat to the part back.

2 is a View looking toward the left in Fig. 1, showing the parts of the casing assembled. Fig. 3 is a horizontal section on line 3 3, Fig. 1. Fig. 4. is a section on line 4 4, Fig. 2. Fig. 5 is a vertical section on line 5 5, Fig. 1.

y In the socket-casing shown in the drawings,

- A indicates the cylindrical metallic shell, and

B the cap, which is provided with a cylindrical portion B, adapted to fit over the end of the shell A, the cap and shell forming the two telescoping parts of the casing. The connecting devices are formed in the overlapping parts of the shell and cap. In the casing shown two forms of connecting devicesare employed, and there are two sets of dev1ces of each form. In one torm oi connectiug devices shown the cap B is provided with.

a lug 0, formed by drawing a portion of the shell radially inward. This lug cooperates with a longitudinal slot D anda transverse slot 1), formed in the shell A. The slot D extends transversely from the slot D, and the two slots open into each other. There are two of this form of connecting device arranged on diametrically opposite sides of the casing. In the other form of connecting devices the cap B is provided with a lug E, formed by drawing the metal of the cap radially inward. This lug cooperates with a longitudinal slot F and a transversely-arranged hole, slot, or recess F, formed in the shell. In this .lorm of connection the recess F is separated from the longitudinal slot F by a section A of the shell, so that the lug E and recess F form a locking device for pre venting relative turning of the parts.

In connecting the parts together the cap B is applied to the shell A, with the longitudinal slots Dand F in register with the lugs O and E, so that as the shell passes into the cap the lugs pass into the longitudinal slots and into alinernent with the transverse slots. The parts are then rotated relatively to each other. As the parts are rotated the lugs 0 enter the transverse slots D, locking the parts together against longitudinal movement. At the same time the lugs E act against the parts A of the shell A, which separates the recesses F from the slots F, springing the shell inward at these points sufficiently to allow the lugs E to enter the slots F. As soon as the lugs E have passed into the slots F the shell springs The shoulders F now cooperate with the lug E to prevent rotation of the parts with relation to each other in eitherdirection until suflicient force is applied to cause the lines may be done before or lug E to spring the shell inward. rts lugs E and recesses F therefore act as spring locking devices to prevent relative rotation of the parts, as well as longitudinal movement with relation to eachother.

In drawing the metal of the shell or cap radially to form the lugs E, I prefer to shear through the metal on transverse parallel lines E and to draw the metal radially either inward or outward between the lines. The lugs thus formed are integral with the shell or cap at their ends and are provided with sides extending transversely and at right angles to the periphery of the shell or cap, which will eifectively cooperate with the transverse sides of the slots F in securely connecting the parts together. The ends of the lugs may also be readily formed to act as cams for springing the shell inward to allow thepassage of the lug into or out of the slot F.

The shearing through the metal on parallel simultaneously with the radial drawing of the metal. To facilitate the drawing, the metal may be annealed by'the application of heat to the points where the lugs are to be formed. The lugs C are formed by drawing the metal radially about a central opening. 1 thus form a hollow cylindrical lug, which may be internally screw-threaded to receive a screw G for engaging and holding theinclosed socket-body in place. This form of lug is therefore of especial advantage, since it enables the use of screwsfor holding the socket-body without requiring the use of the yokes or other separate devices employed in previous sockets to receive the screws.

While I have shown four sets of connecting devices, it will be understood that this number is not essential and that the number of connecting devices may be varied as desired. For instance, the lugs E and the cooperating slots may be omitted and the lugs C and the cooperating slots D D be relied upon to hold the parts together, or the lugs O and the cooperating slots may be omitted and the lugs E and slots F F be relied upon to hold the parts together. In case only two sets of the connecting devices are employed the sets may be duplicates of each other or may be of difierent forms.

It will be understood that the lugs C or E may be drawn radially inward or radially outward and that the lugs may be formed in either the cap or the shell, the cooperating-slots be- In the structure described the parts are held together at four points and are held rigidly together, so that they cannot sway or tip. The fastening devices do not depend upon screws which will work loose under jarring and may be more cheaply made than the constru'ction in common use. I

What I claim, and desire to secure by Letters Patent, isv 1. A casing for incandescent-lamp sockets, consisting of telescoping shell and cap of sheet metal, one or more radially-extending integral cylindrical lugs on one part internally screwthreaded to receive body-holding screws, and a slot or slots in the other part cooperating with said lug or lugs to hold the parts of the casing together.-

2. A casing for incandescent-lamp sockets,

consisting of telescoping shell and cap of sheet metal, one or more radially-extending integral cylindrical lugs on one part internally screwthreaded to receive body-holding screws, one or more cooperating slots in the other part in combination with a locking device consisting of a projection formed on'one part and springing into a corresponding hole or slot in the other part. 1 In testimony whereof .l have affixed m y signature in presence of two witnesses.

NORMAN MARSHALL.

Witnesses: IRA L. FIsH, KATHARINE A. DUGAN. 

